"People intentionally dumped (these) in the river and also littered," Pregracke said. "Even 100 miles away, (trash) will find its way into a creek or a storm drain and into, ultimately, the Mississippi River."

For Pregracke, removing this debris has become his life's work. Sometimes called "The Rivers' Garbageman," he lives on a barge about nine months out of the year with members of his 12-person crew. Together, they organize community cleanups along rivers across the country.

"The garbage got into the water one piece at a time," Pregracke said. "And that's the only way it's going to come out."

It's a dirty job, but Pregracke, 38, took it on because he realized that no one was doing it. It began as a solo effort, and over the years his energy, enthusiasm and dedication have helped it grow. To date, about 70,000 volunteers have joined his crusade, helping him collect more than 7 million pounds of debris through his nonprofit, Living Lands & Waters.

On average, Pregracke says he organizes 70 cleanups a year in 50 communities. The cleanups are posted on the nonprofit's website, Facebook and other outlets so people know where and when they can volunteer.

Throughout the year, Pregracke's flotilla travels on rivers throughout the Midwest. For the past three years, the group has visited Memphis, Tennessee, each spring to help clean up a harbor on the Mississippi River where the waters are thick with debris. During their most recent visit, they collected more than 120,000 pounds of garbage in 14 working days.